"Gunmen exchanged fire with Afghan security forces and the attack is ongoing," he added.

The appeals court office is situated next to the powerful governor Atta Mohammad Noor's office. A local journalist, Esmatullah Koshar, who runs the Kabul Pressistan media, reported of one killed and at least seven wounded in the attack.

He also reported of blasts and heavy armed clashes from inside the building, where the gunmen are still holed up.